Why Can't We: Genetically Modify Plants to Eat Up CO2

Plants take in a lot of CO2 and release a lot of oxygen. And while they’re doing this good deed, they trap carbon for the life of the plant. But when, say, a huge tree falls over and dies, that carbon is released into the atmosphere. Scientists want to figure out how to lessen the effects of climate change by engineering plants to keep carbon locked away postmortem.

According to Christer Jansson, a senior staff scientist at ­Lawrence Berkeley National Laboratory in California, the best way to do that is to give plants deeper roots. “Anything more than two feet transfers the carbon into the soil for long-term sequestration,” says Jansson. “If it’s left undisturbed, that’s where it will stay for as long as a millennium.” The best candidates are widespread shallow-rooted crops—corn, rice, and grasses used in the production of biofuel—which would be modified to soak up the carbon that deforestation and the burning of fossil fuels release into the atmosphere.

Experiments with enhancing CO2 ­uptake are under way, and Jansson believes that by 2050 engineered plants could sequester all eight-plus gigatons of carbon that humans are ­responsible for each year. The idea is promising, says ­Rattan Lal, director of Ohio State University’s ­Carbon Management and Seques­tration Center, but perhaps not entirely sufficient. “Because the problem is so vast, we’re going to need hundreds of solutions to bring carbon back to preindustrial levels. Genetically engineered plants is just one.”